1. Technical Field
This invention relates generally to a method and apparatus for separating valuable material from unwanted material in a mixture, such as a pulp slurry.
2. Description of Related Art
In many industrial processes, flotation is used to separate valuable or desired material from unwanted material. By way of example, in this process a mixture of water, valuable material, unwanted material, chemicals and air is placed into a flotation cell. The chemicals are used to make the desired material hydrophobic and the air is used to carry the material to the surface of the flotation cell. When the hydrophobic material and the air bubbles collide they become attached to each other. The bubble rises to the surface carrying the desired material with it.
The performance of the flotation cell is dependent on the bubble surface area flux in the collection zone of the cell. The bubble surface area flux is dependent on the size of the bubbles and the air injection rate. Controlling the bubble surface area flux has traditionally been very difficult. This is a multivariable control problem and there are no dependable real time feedback mechanisms to use for control.
The mineral recovery of such a process can be highly dependent on the mineral particle size distribution entering the flotation cell. Typically, coarse and fine particles recovery can be significantly less than the optimal particle size. Mining operations routinely discharge large well liberated particles to the tailings pond.
The assignee of the present application has designed a new machine and process for recovering valuable minerals from mineral rich pulp slurry. This slurry could be any type of slurry being air conveyed ground minerals or an aqueous mixture for example. This mineral rich slurry is put into contact with a functionalized polymer surface which has been engineered to attract the mineral of interest. The surface could be anything from an engineered bubble to a flat plate. The unwanted material is washed away and only the desirable mineral is left on the surface. The enriched surface is then treated so that the mineral is released and collected. The polymer surface can then be reused.
One of the design challenges is to design a surface that has maximum surface area and yet will survive in an industrial environment. Therefore it must be strong, wear resistant, and be able to pass large amount of rejected solids while capturing the value material.
There is a need in the industry to provide a better way to separate valuable material from unwanted material, e.g., including in such a flotation cell, so as to eliminate problems associated with using air bubbles in such a separation process.